clean up graphics helpers

src/graphics/host_gpu/vulkanCommon.h

@@ -24,8 +24,6 @@
 
 namespace Libs::Graphics {
 
-using VulkanMemoryBarrier = vk::MemoryBarrier;
-
 vk::Format  VulkanFormat(Prospero::BufferFormat guest_format);
 void        RequireVulkanSuccess(vk::Result result, const char* operation);
 vk::ShaderModule CompileSPV(std::span<const uint32_t> code, vk::Device device);